This invention relates to novel 1,9-dihydroxyoctahydrophenanthrenes and 1-hydroxyoctahydrophenanthren-9-ones and derivatives thereof having analgesic properties useful for administration to mammals including humans, and to intermediates useful for the preparation of said compounds.
Despite the current availability of a number of analgesic agents, the search for new and improved agents continues, thus pointing to the lack of an agent useful for the control of broad levels of pain and accompanied by a minimum of side-effects. The most commonly used agent, aspirin, is of no practical value for the control of severe pain and is known to exhibit various undesirable side-effects. Other, more potent analgesic agents such as d-propoxyphene, codeine, and morphine, possess addictive liability. The need for improved and potent analgesic agents is, therefore, evident.
The analgesic properties of 9-nor-9.beta.-hydroxyhexahydrocannabinol and of the other cannabinoid structures, such as .DELTA..sup.8 -tetrahydrocannabinol (.DELTA..sup.8 -THC) and its primary metabolite, 11-hydroxy-.DELTA..sup.8 -THC, have been reported by Wilson and May, Absts. Papers, Am. Chem. Soc., 168 Meet., MEDI 11 (1974), J. Med. Chem., 17, 475-476 (1974), and J. Med. Chem., 18, 700-703 (1975).
U.S. Pat. Nos. 3,507,885 and 3,636,058, issued Apr. 21, 1970 and Jan. 18, 1972, respectively, describe various 1-hydroxy-3-alkyl-6H-dibenzo-[b,d]pyrans having at the 9-position substituents such as oxo, hydrocarbyl and hydroxy or chloro, hydrocarbylidene, and intermediates therefor.
U.S. Pat. No. 3,649,650, issued Mar. 14, 1972, discloses a series of tetrahydro-6,6,9-trialkyl-6H-dibenzo[b,d]pyran derivatives having at the 1-position an .omega.-dialkylaminoalkoxy group active as psychotherapeutic agents.
German Specification No. 2,451,934, published May 7, 1975, describes 1,9-dihydroxyhexahydrodibenzo[b,d]pyrans and certain 1-acyl derivatives thereof having at the 3-position an alkyl or alkylene group, as hypotensive, psychotropic, sedative and analgesic agents. The precursor hexahydro-9H-dibenzo[b,d]pyran-9-ones used in their preparation, and which are reported to have the same utility as the corresponding 9-hydroxy compounds, are described in German Specification No. 2,451,932, published May 7, 1975.
U.S. Pat. No. 3,856,821, issued Dec. 24, 1974, describes a series of 3-alkoxy substituted dibenzo[b,d]pyrans having antiarthritic, antiinflammatory and central nervous system activity.
Bergel et al., J. Chem. Soc., 286-287 (1943) investigated the replacement of the pentyl group at the 3-position of 7,8,9,10-tetrahydro-3-pentyl-6,6,9-trimethyl-6H-dibenzo[b,d]pyran-1-ol by alkoxy (butoxy, pentyloxy, hexyloxy and octyloxy) and found that it led to biological inactivity. The hexyloxy derivative was reported to exhibit feeble hashish activity at 10 to 20 mg./kg. The remaining ethers showed no activity in doses up to 20 mg./kg.
In a more recent study, Loev et al., J. Med. Chem., 16, 1200-1206 (1973) report a comparison of 7,8,9,10-tetrahydro-3-substituted-6,6,9-trimethyl-6H-dibenzo[b,d]pyran-1-o ls in which the 3-substituent is --OCH(CH.sub.3)C.sub.5 H.sub.11 ; --CH.sub.2 CH(CH.sub.3)C.sub.5 H.sub.11 ; or --CH(CH.sub.3)C.sub.5 H.sub.11. The ether side chain containing compound was 50% less active in central nervous system activity than the corresponding compound in which the alkyl side chain is directly attached to the aromatic ring, rather than through an intervening oxygen atom; and 5 times as active as the compound in which oxygen is replaced by methylene.
Co-pending U.S. patent application Ser. No. 819,471 filed July 27, 1977 discloses a series of 1,9-hydroxyhexahydrodibenzo[b,d]pyrans and intermediates therefor having analgesic and other therapeutic activities. Co-pending U.S. patent application Ser. No. 777,928 filed Mar. 15, 1977 discloses a series of 1,9-dihydroxyoctahydrobenzo[c]quinolines and intermediates therefor also having analgesic and other therapeutic activities.
Mechoulam and Edery in "Marijuana", edited by Mechoulam, Academic Press, New York, 1973, page 127, observe that major structural changes in the tetrahydrocannabinol molecule seem to result in steep reductions in activity.
Paton, in Annual Review of Pharmacology, 15, 192 (1975) presents generalizations on structure-action relationships among cannabinoids. The presence of the gem dimethyl group in the pyran ring is critical for cannabinoid activity and substitution of N for O in the pyran ring removes activity. Paton also reports that substitution of a --CH.sub.2 -- group for oxygen in the pyran ring to produce phenanthrenes has not been examined.